Method For Regulating the Drive of a Shearing or Heading Machine

ABSTRACT

In a method for controlling the drive of a shearing or heading machine for cutting a round, as a function of manipulated variables such as the movement speed of the cantilever arm, the position of the cutting tools and/or the power consumption of the drive motors and the pressure in hydraulic actuating cylinders, a minimum and a maximum target value are determined for the movement speed of the cantilever arm, and at least two factors each having values of between 0 and 1 are calculated for the manipulated variables as a function of measurement values, the measurement values at least comprising cutting tool position data compared to set data corresponding with a set profile, motor load measurement data and cantilever arm movement speed measurement data, and the movement speed of the cantilever arm is controlled as a function of the product of the set speed and the respectively calculated factors.

The invention relates to a method for controlling the drive of ashearing or heading machine for cutting a round, as a function ofmanipulated variables such as the movement speed of the cantilever arm,the position of the cutting tools and/or the power consumption of thedrive motors and the pressure in hydraulic actuating cylinders.

For controlling the advance heading of a shearing or heading machine, anumber of more or less general methods have become known. From DE 36 31087, it can be taken that the operation and state data of a winning orpartial-cut cutting machine used in underground mining are continuouslydetected and fed to a computer for evaluation. From those data, thecomputer determines the cause of failure using a diagnose system, andsubsequently initiates complex measures to remove the failure. Thecomputer described there, however, above all serves to non-erasablystore the failure and/or its causes until removal in order tosubsequently enable the taking of suitable measures even after theoccurrence of a failure. Such diagnose, in the main, requires complexevaluations and specific programming tailored to a specific shearing orheading machine. Detailed algorithms are not offered there. DE 29 19 499C2 shows and describes a method for controlling the cutting horizon ofroll cutter machines, in which the cutter force is continuously capturedon the rotating roll body and compared with given limiting values. Whenexceeding those limiting values, a change in the height adjustment isinitiated.

EP 0 807 203 B1 finally shows and describes a system for the continuouscontrol of a mining or advance working machine, which includes a numberof measuring sensors and, in particular, angle encoders and linearencoders in order to capture the position of the cutter head of acantilever arm. Via a defined computation program, adjustment values aregenerated for the proportional control valves of the drive units suchas, for instance, the pivoting cylinders of the cutter bar or the lineardrive of the cutter head to thereby ensure the compliance with apreselected profile.

The invention aims to provide a method of the initially defined kind,which will do with a minimum of parameters to be each defined in amachine-specific manner, and which can be universally used for differentconstructions of mining or advance working machines. Essential to thecontrol algorithm proposed by the invention is to be the fact that theparameters are merely dependent on the drive itself and on the machinegeometry, but independent of the actual conditions at the mine face, sothat the adjustment values respectively required for different machinescan be input individually and without complex programming knowledge. Tosolve this object, the method according to the invention of theinitially defined kind essentially consists in that a minimum and amaximum target value are determined for the movement speed of thecantilever arm, that at least two factors each having values of between0 and 1 are calculated for the manipulated variables as a function ofmeasurement values, said measurement values at least comprising cuttingtool position data compared to set data corresponding with a setprofile, motor load measurement data and cantilever arm movement speedmeasurement data, and that the movement speed of the cantilever arm iscontrolled as a function of the product of the set speed and therespectively calculated factors. By specifying each a minimum and amaximum target value for the movement speed, it will do to determinethese values once, for instance by the aid of a valve description. Theminimum target value for the pivot speed in this case corresponds tothat control current for the proportional control valves, which causes amovement at all. The respective maximum target value for the movement ofthe cutting unit, in general, amounts to 100% of the machine-specificmaximum pivot speed, yet may also be adjusted to a defined speed on thebasis of cutting technical criteria. By determining a plurality ofmultiplicatively linked factors for different measurement values, anextremely precise control is achieved, which, in the event of deviationsof individual ones of these values, enables the respective cancellationof the target values until stoppage. The individual factors may eachassume values of between 0 and 1, wherein the fact that already a singleone of these factors assumes the value of 0 will cause the pivot speedto be accordingly reduced to 0, due to the multiplicative linkage.

Advantageously, the calculation of the individual factors is performedin a manner that the individual factors each take into account aseparate measurement value for the manipulated variables such as, e.g.,the motor load, the distance of the position coordinates from targetcoordinates for the profile to be mined, the pivot speed of thecantilever arm and/or the rotational speed of the mining tools. This,for instance, results in such a factor k assuming a value of between 0and 1 and cancelling the movement as soon as more than the nominal loadis taken up. Another multiplicatively linked factor k, which maylikewise assume values of between 0 and 1, may cancel the movement assoon as the cutting unit approaches a target point, in order to stopsaid movement in time and/or enable a reversal of the direction ofmovement. Finally, a further k-value can be determined as a function oftime measurement values, which becomes effective after an imminentblockage or at the occurrence of a blockage and, in the following, willtrigger a complex blockage algorithm for a starting control.

In an advantageous manner, the method is performed such that measurementvalues for changes in the motor load, pivot speed and/or rotationalspeed are determined over time and fed to a freely programmable switchmechanism and to the drive control as separate manipulated variables soas to enable not only the safe detection of the actual load on thedrive, such as, e.g., the current of the cutting motor, but alsotime-dependent changes of this load. In this case too, it is againfeasible to preset suitable limit values by selecting the respectivek-values for a particular machine type, and to indicate by a nominalvalue the nominal load of the drive sought during the cutting procedure.

That load on the drive which is to cause the control to start theblockage protection algorithm may likewise be defined individually andtrigger the respective protection mechanisms, as this limit loadcontinues over a defined time. To this end, the configuration ispreferably devised such that at least one delay time is feedable to thefreely programmable switch mechanism as a manipulated variable via whichthe starting speed is kept at or near the minimum set movement speedupon detection of a blockage. The linkage of the target values for themovement speed, which may basically be target values of the controlcurrent for the proportional control valves of the hydraulic drive, withindividually defined factors can be accordingly supplemented by addingfurther factors in order to achieve an enhanced accuracy of the control.The invention basically aims to control the movement speed of thecutting unit always in a manner that the cutting drives will possiblyalways be operated within the nominal load range, i.e. at the optimumpower consumption and the correct operating pressure, whereby cuttingtechnically relevant maximum speeds are not to be exceeded.

The control as a function of the nominal load as effected according tothe invention serves to adapt the movement speed of the cutting unitsuch that the cutting motor itself will possibly be operated within thenominal load range. The coordinate control and the respective factorlikewise are to safeguard that the target points on the cutting path bereached with a defined geometric accuracy. The target or inversionpoints in this case are not to be overtravelled and the movement speedis to be taken back accordingly closely downstream of the target point.

The separate blockage control provided by the invention is, however, ofessential importance. In the event of an instantaneous overload orblockage of the cutting motor, it will, as a rule, do to briefly placethe cutting unit out of engagement by stopping the advance headingspeed. The cutting unit is thus relieved, whereupon the round may becontinued again. If, however, a particular load value, i.e. the loadvalue critical for a blockage, is exceeded over a defined time, ablockage protection algorithm can be activated to recognize an actualblockage well before its occurrence. In this case, the cutting unit canbe placed out of engagement as rapidly as possible in order to preventan imminent blockage of the cutting motor. Wherein, if no movement inthe counter direction is required, the advance heading movement mustmerely be stopped, whereupon slow starting can be effected as a functionof the given time adjustment values to cause the cutting unit to reenterinto full engagement only upon expiration of a delay time. At the sametime, the k-factor may define a real speed portion to which the cuttingunit is to be delayed when reentering into engagement after a blockageat the blockage point. The cutting speed can, thus, be initially reducedafter the delay time to be only increased to full speed after a furthertime interval, the delay time usually being the time that is still runat minimum speed by the cutting unit after having passed the blockagepoint, before its movement can again be accelerated to maximum speed.The relevant time that is to trigger such a blockage protectionalgorithm can be individually set and signifies the time over which theload on the drive must be exceeded in order to trigger the blockagealgorithm for subsequent control.

Similarly, for approaching the target point based on the positionmeasurement data detected, it is possible to not only define a distanceto the cutting unit to the target point, starting from which themovement of the cantilever arm will be reduced accordingly, but alsoadjust a tolerance value by which the target point has to be reachedbefore enabling the next movement.

In the event of a blockage or imminent blockage, the respective positioncoordinates of the blockage point can be determined, and a separate timeinterval can be adjusted, within which the time unit accelerates themovement to maximum speed after a new passage of the blockage point, andhence again releases the generally applied control.

Hence results, in the main, that different machine types can be takeninto account by a defined, small number of individual parameters andthat no complete, complex controls have to be programmed for everymachine type. Unlike the usual two-position controls provided onpartial-cut cutting machines, the parameters used in the algorithmaccording to the invention are each of physical relevance and relativelysimple to determine. These parameters according to the invention aresubstantially only dependent on the drive unit and on the machinegeometry, and no additional corrections have to be made as a function ofengagement or mine face conditions. Therefore, machines of the same typecan always be adjusted with identical values. Due to the independence ofactual on-site conditions, the control algorithm will respond tochanging rock or engagement conditions in a largely insensitive mannerduring a round, the described algorithm enables the standardization ofthe control concept for different machine types, thus substantiallyenhancing the maintainability of the systems. At the same time, anextremely safe and sensitive detection of critical limit values isenabled by the multiplicative linkage of the individual parameters so asto safely avoid damage and long downtimes.

1-4. (canceled)
 5. A method for controlling the drive of a shearing orheading machine for cutting a round as a function of manipulatedvariables, comprising the steps of: determining a minimum target valueand a maximum target value for movement speed of a cantilever arm of themachine; calculating at least two factors, each of said factors havingvalues of between 0 and 1, for manipulated variables as a function ofmeasurement values, wherein said manipulated variables are one or moreof movement speed of the cantilever arm, position of cutting tools ofthe machine, power consumption of drive motors of the machine, andpressure in hydraulic actuating cylinders of the machine, and whereinsaid measurement values are one or more of cutting tool position datacompared to set data corresponding with a set profile, motor loadmeasurement data, cantilever arm movement speed measurement data,cantilever arm pivot speed measurement data, mining tools rotationalspeed measurement data, and distance of position coordinates from targetcoordinates for the profile to be mined; and controlling the movementspeed of the cantilever arm as a function of a product of a set speedand the respectively calculated factors.
 6. A method according to claim5, wherein each of said factors takes into account a separatemeasurement value for the manipulated variables.
 7. A method accordingto claim 5, wherein measurement values for one or more of changes inmotor load, changes in pivot speed, and changes in rotational speed, aredetermined over time, and wherein said measurement values for said oneor more changes in motor load, changes in pivot speed, and changes inrotational speed determined over time are fed to a freely programmableswitch mechanism, and to a drive control of the machine, as separatemanipulated variables.
 8. A method according to claim 6, whereinmeasurement values for one or more of changes in motor load, changes inpivot speed, and changes in rotational speed, are determined over time,and wherein said measurement values for said one or more changes inmotor load, changes in pivot speed, and changes in rotational speeddetermined over time are fed to a freely programmable switch mechanism,and to a drive control of the machine, as separate manipulatedvariables.
 9. A method according to claim 7, further comprising thesteps of: feeding at least one delay time to the freely programmableswitch mechanism as a manipulated variable, and upon detection of ablockage, keeping a starting speed of the movement of the cantilever armat or near the minimum target value for movement speed during said delaytime.
 10. A method according to claim 8, further comprising the stepsof: feeding at least one delay time to the freely programmable switchmechanism as a manipulated variable, and upon detection of a blockage,keeping a starting speed of the movement of the cantilever arm at ornear the minimum target value for movement speed during said delay time.